Pretty good article, but he left out a couple of forms of communication and didn't include the different dialects for some.

There is a version of the up-nod used mainly by southern men driving pickup trucks to say hello or "hey man". Another form of this same greeting is called the "thumb hooked in the steering wheel wave", which is used while steering with one hand. The other four finger are raised while the thumb remains hooked the steering.

In 1978 while attending electronics school, I made a friend who was a recent army retiree and yankee*. He wondered why his neighbors only responded with a cold eye when he would drive by in a wave at them. He found his answer to their apparent unfriendliness once he had obtained a 1970 model Chevrolet pickup with a few rust spots on it. His neighbors gladly returned his greeting whenever he passed by from then on.

I would like to hear from some non-US board members about their customs in the man-to-man communications.

Funny you should post this today, as my wife and I had a hand sign communication failure today.

We have a big yard, about 8 acres that is mowed, I've been killing myself this week trying to get caught up so she offered to mow for me ... yeah me, yeah her. Anyway, she was mowing I was weed-eating and she drove by and gave me a choking hand sign, I thought she meant she'd rather be choked than mow, i.e this sucks. So keep weed-eating ... she goes by again and does it, ok I saw it the first time. So she drive by again and say "Did you not see me do this (does the choke sign), that means I'm thirsty!!" So I'm like no it not and I did the glass tip near the mouth sign and said that mean your thirsty.So she said I said I was choking so I needed a drink ... I said it could have meant you needed the Heimlich maneuver too, this (and did the glass tilt again) means you're thirsty or need a drink.

Another common sign is for motorcycle riders passing each other is the "down peace", as you pass each other going in opposite direction. You hold you left hand down the the side and give the peace sign. (Unless they are riding a crotch rocket. Then you ignore them ... LOL.